I personally would not invest anymore in DDR RAM. If you have money, I'd upgrade to a PCI-E/DDR2 based rig.

Note that most of the current G.Skill users are DDR2, and I dare say that a large percentage of the DDR G.Skill users use the HZ's, which run at PC4000 (DDR 500) speeds. I don't think there are many folks using PC3200 (DDR 400) G.Skill RAM. G.Skill is more targeted toward overclockers, thus the PC4000 is pretty common for DDR.

Most people have G.Skill Hz's which are DDR2. $120 on outdated ram is kind of a waste.

Well, it's only a waste if you're going to abandon a DDR-based system. But if you're going to keep your DDR-based system for quite some time, and will be doing more RAM-intensive tasks, then it's not a bad investment. It's cheaper than building a new DDR2-based system that may or may not be necessary.